This invention is generally directed to toner and developer compositions, and more specifically, the present invention is directed to developer and toner compositions containing a polyesteramide-siloxane resin, and processes for the preparation thereof. In embodiments, there are provided in accordance with the present invention, toner compositions comprised of certain polyester-siloxane resins, charge controlling agents and pigment parities comprised of, for example, carbon black, magnetites, or mixtures thereof, cyan, magenta, yellow, blue, green, red, brown components, or mixtures thereof thereby providing for the development and generation of black and/or colored images. In embodiments, there are provided in accordance with the present invention a polyesteramidesiloxane resin, as illustrated by the following formulas I,II and III. ##STR2## wherein R is an aryl with, for example, 6 to about 30 carbon atoms, such as phenyl, naphthyl, benzyl, terephthaloyl, isophthaloyl or alkyl; R' is an alkyl group with, for example, 1 to about 25 carbon atoms, an alkylene, such as for example with from 1 to about 25 carbon atoms like ethylene, propylene, butylene, and the like, or an alkylene oxide with, for example, 1 to about 25 carbon atoms, such as diethylene oxide, triethyleneoxide, polyoxypropylene, mixtures thereof, and the like; and m, n and o represent the number of monomer segments. The toner compositions of the present invention in embodiments possess a number of advantages including oilless characteristics, that is the ability of a toner not to offset onto the fuser rolls with minimal, or preferably no release agents present on the fuser rolls. Additionally, in embodiments the toner compositions of the present invention possess low melting properties, excellent blocking characteristics, excellent admix characteristics, excellent nonvinyl offset properties, and low relative humidity sensitivity such as from about 1.01 to about 2.3. The toner compositions of the present invention can in embodiments be generated by a process involving the melt polycondensation of about 1 mole equivalent of diacid or diester, such as terephthalic acid or dimethylterephthalate, with from about 0.95 to 2 moles of glycol, such as 1,2-propylene glycol, diethylene glycol mixtures thereof and the like, and from about 0.01 to about 0.2 mole equivalent of an .gamma.-aminoalkyl siloxane such as illustrated by the formulas that follow immediately ##STR3## wherein n represents the number of repeating segments, and is, for example, a number of from about 10 to about 1,000.
The polyesteramide-siloxane exhibits, for example, a number average molecular weight of from about 1,500 to about 50,000 grams per mole as measured by vapor pressure osmomotery, and a glass transition temperature of from about 40.degree. C. to about 80.degree. C., and more preferably from about 50.degree. C. to about 65.degree. C. as measured by a Differential Scanning Calorimeter.
Examples of specific advantages of the toner composition of the present invention comprised of polyesteramide-siloxanes, include oilless characteristics, that is for example there can be avoided the utilization of release agents on the fuser oils, or only minimal use of release agents on the fuser roll is selected, such as from about 0.1 percent to about 50 percent of the release agents, depending on the type of fuser used. Other advantageous include low fusing temperatures, such as from about 120.degree. C. to about 140.degree. C., and therefore lower fusing energies are required for fixing, thus enabling less power consumption during fusing, and permitting extended lifetimes for the fuser system selected. Furthermore, the toner compositions of this invention possess in embodiments a broad fusing latitude, such as from about 40.degree. C. to about 100.degree. C., with minimal or avoidance of release oil, which inhibits the toner from offsetting onto the fuser rollers usually associated with ghosting or background images on subsequent copies. Moreover, the fused image obtained from the toner composition of the present invention in embodiments does not substantially offset to vinyl covers, such as those utilized for notebook binders, and possess a low humidity sensitivity ratio of from about 1 to about 2.3 as calculated by the ratio of the triboelectric charge (in microcoulombs per gram) of the developer after being placed in a chamber of 20 percent humidity for 48 hours to the triboelectric charge (in microcoulombs per gram) of the developer after being placed in a chamber of 80 percent humidity for 48 hours.
In designing resins for toner composition, it is generally desired that the glass transition temperature of the resin be from about 50.degree. C. to about 65.degree., and preferably no less than about 55.degree. C. so that, for example, the toner particles do not aggregate, coalesce or block during manufacturing, transport or storage, or until the toner is needed for fixing. Moreover, low relative humidity sensitivity of toners are desired such that the triboelectric charge is stable to changes in environmental humidity conditions. Copiers and printers equipped with pressure fuser rolls normally employ release agents, such as silicone oil and the like, to prevent the toner from offsetting on the rolls during the transfix step. Toner offset onto the fuser rolls can cause ghosting and image deterioration on subsequent copies and such offset also reduces the lifetime of the fuser. Therefore, especially with xerographic copiers and printers utilizing pressure fixing rollers, release agents, such as silicone oils, are replenished regularly since some of the oil transfers onto the paper during transfix and is lost. There is a need for fuser rolls which do not necessitate the use of release agents, such as silicone oil on the fuser rolls, hence reducing the need of silicone oil and replenishing mechanism thereof, thereby reducing the cost of such equipment. With the toners of the present invention, such fuser release agents, specifically agents like an .gamma.-alkylaminosiloxane oil is minimized or avoided as the toner will not usually offset onto the fuser rolls during the transfix step. This is accomplished, in the present invention in embodiments, by providing an oilless toner wherein the resin is comprised of a polesteramide-siloxane material. Moreover, the toner of the present invention displays other advantages as indicated herein, such as low fixing temperatures of from about 120.degree. C. to about 140.degree. C., high gloss such as from about 50 gloss units to about 80 gloss units, nonvinyl offset properties, and low relative humidity sensitivity such as from about 1.01 to about 2.5. These and other advantages are attained by the toner compositions of this invention, which compositions are comprised of a pigment, optionally a charge control agent, a polyesteramide-siloxane resin derived from a polyester and alkylaminosiloxane, and optional known toner additives, which toner exhibits ramless features such as the reduced need of fuser release agents of from about 0 to about 50 percent, low fixing temperature of from about 120.degree. C. to about 140.degree. C., high gloss such as from about 50 gloss units to about 80 gloss units, nonvinyl offset properties and low relative sensitivity such as from about 1.0 to about 2.3.
Polyesteramide resins are known, reference in U.S. Pat. No. 4,601,966, which discloses toner and developer compositions with an amorphous, random polyesteramide containing amide linkages in the polymer backbone, and is derived from certain dicarboxylic acids, compounds containing primary amino groups and compounds containing hydroxyl groups, however, polyesteramide-siloxane resins are not disclosed and also the polyesteramide of this reference is comprised of ester and amide linkages throughout the backbone of the resin. Furthermore, the '966 patent does not disclose the advantages of oilless or low humidity sensitivity. In the present invention, in embodiments there are provided toners comprised of polyesteramide-siloxane resins wherein a polyester segment is linked by an amido moiety to a siloxane moiety, and wherein oilless features are attained accompanied by low relative humidity sensitivity, and thus differs, for example, from the '966 patent wherein a siloxane release oil is not chemically linked to the polyesteramide resin for oilless functionality. In U.S. Pat. No. 4,954,408, the disclosure of which is totally incorporated herein by reference, there is disclosed a toner composition comprised of a pigment, charge control agent and a styrene-butadiene-siloxane resin. The toner composition of the ' 408 invention mentions advantages, such as oilless characteristics, however, the toners of the '408 patent display fixing temperatures of from about 140.degree. C. to about 160.degree. C., and are believed to be inferior for low melt applications wherein low fixing temperatures of from about 120.degree. C. to about 145.degree. C., and wherein high gloss of from about 40 to about 80 gloss units are desired. Furthermore, the siloxane portion is linked via a carbon-carbon bond and no amide linkages are present in the resins of the '408 patent. This differs from the present invention wherein the siloxane linked to the polyester resin is a .gamma.-alkylaminosiloxane forming an amide linkage. With the toner of the present invention, the preferred silicone oil in embodiments is chemically linked to a toner resin such as a polyester. Furthermore, with the toner of the present invention in embodiments, a low fixing temperature of from about 120.degree. C. to about 145.degree. C., and high gloss of from about 40 to about 80 gloss units are attained, and which gloss is not believed to be attainable with the toner resin of the '408 patent.
Specifically, in one embodiment, the present invention relates to a toner composition comprised of a pigment, charge control agent and polyesteramide-siloxane resins as illustrated with reference to formula 1 with low fixing of from about 120.degree. C. to about 140.degree. C., high gloss such as from about 50 gloss units to about 80 gloss units as measured by the Garner Gloss metering unit, nonvinyl offset properties, and in addition low relative humidity sensitivity such as from about 1.0 to about 2.3, and ramless characteristics such as a reduction of from about 50 percent to about 100 percent of release agents used for fuser rolls.